app.py

from fastapi import FastAPI, Request
from pydantic import BaseModel
from collections import deque
from datetime import datetime, timedelta
from typing import Optional
import uuid

app = FastAPI(title="Chat Handshake API")

# ---------- Configuration ----------
EXPIRATION_MINUTES = 5
MAX_MESSAGES = 1000
LOG_FILE = "activity.log"

# ---------- In-memory message storage ----------
messages = deque(maxlen=MAX_MESSAGES)

# ---------- Pydantic model ----------
class Message(BaseModel):
    type: str                 # "offer", "answer", "chat", "connect"
    from_user: str
    to_user: Optional[str] = None
    content: Optional[str] = None

# ---------- Helper functions ----------
def expire_messages():
    cutoff = datetime.utcnow() - timedelta(minutes=EXPIRATION_MINUTES)
    while messages and messages[0]["timestamp"] < cutoff:
        messages.popleft()

def log_message(msg: dict, ip: str):
    with open(LOG_FILE, "a") as f:
        f.write(f"{datetime.utcnow()} {ip} {msg}\n")

# ---------- API Endpoints ----------

@app.post("/write")
async def write_message(msg: Message, request: Request):
    expire_messages()
    message_id = str(uuid.uuid4())
    entry = {
        "id": message_id,
        "type": msg.type,
        "from": msg.from_user,
        "to": msg.to_user,
        "content": msg.content,
        "timestamp": datetime.utcnow()
    }
    messages.append(entry)
    log_message(entry, request.client.host)
    return {"status": "ok", "id": message_id}

@app.get("/read")
async def read_messages(username: str):
    expire_messages()
    not_mine = [m for m in messages if m["from"] != username]
    return {"messages": not_mine}

@app.get("/readall")
async def read_all_messages():
    expire_messages()
    return {"messages": list(messages)}

@app.post("/retract")
async def retract_message(message_id: str):
    global messages
    messages = deque([m for m in messages if m["id"] != message_id], maxlen=MAX_MESSAGES)
    return {"status": "ok"}